Lithium ion battery negative electrode active material

The present invention relates to a lithium ion battery negative electrode active material that includes an Si phase, an Si—Zr compound phase, an Si—X compound phase, and an Sn—Cu compound phase, X being at least one element selected from the group that consists of Fe, Ni, Co, Mn, Ti, V, and Cr, the Sn—Cu compound phase fraction of the whole being 0.1-18 mass %, and the Si phase fraction being 10-90 mass %.